paper

Common ( $I ¨ $ , $I ¨ $ ) Band Folding and Surface Reconstruction in FeAs-Based Superconductors

arXiv:2104.13745 · doi:10.1088/0256-307X/38/5/057404

Abstract

High resolution angle-resolved photoemission spectroscopy (ARPES) measurements are carried out on CaKFe $_{4}$ As $_{4}$ , KCa $_{2}$ Fe $_{4}$ As $_{4}$ F $_{2}$ and (Ba $_{0.6}$ K $_{0.4}$ )Fe $_{2}$ As $_{2}$ superconductors. Clear evidence of band folding between the Brillouin zone center and corners with a ( $I ¨ $ , $I ¨ $ ) wave vector has been found from the measured Fermi surface and band structures in all the three kinds of superconductors. A dominant $2 \times 2$ surface reconstruction is observed on the cleaved surface of CaKFe $_{4}$ As $_{4}$ by scanning tunneling microscopy (STM) measurements. We propose that the commonly observed $2 \times 2$ reconstruction in the FeAs-based superconductors provides a general scenario to understand the origin of the ( $I ¨ $ , $I ¨ $ ) band folding. Our observations provide new insights in understanding the electronic structure and superconductivity mechanism in iron-based superconductors.

15 pages, 4 figures

Common (I¨,I¨) Band Folding and Surface Reconstruction in FeAs-Based Superconductors

Abstract

Common ( $I ¨ $ , $I ¨ $ ) Band Folding and Surface Reconstruction in FeAs-Based Superconductors